Bug 269509 – Wrong chain F{32,64}Sub + F{32,64}Copysign when rhs is NaN in BBQ JIT mode

• Component: WebAssembly
• Status: RESOLVED FIXED

[Marcus Plutowski]

rdar://120780768

Tested on commit 9fb944e082ca85e9c509d60d879e898476822bd8.

Below the Poc:

```
// (module
//     (type (func (param f64) (result f64)))
//     (func (type 0) (local f64)
//         (local.set 1 (local.get 0))
//         (local.set 0 (f64.sub (local.get 0) (f64.const nan)))
//         (local.set 1 (f64.copysign (local.get 1) (local.get 0)))
//         (local.get 1)
//     )
//   (export "poc" (func 0))
// )

const wasm_code = new Uint8Array([0, 97, 115, 109, 1, 0, 0, 0, 1, 6, 1, 96, 1, 124, 1, 124, 3, 2, 1, 0, 7, 7, 1, 3, 112, 111, 99, 0, 0, 10, 33, 1, 31, 1, 1, 124, 32, 0, 33, 1, 32, 0, 68, 0, 0, 0, 0, 0, 0, 248, 127, 161, 33, 0, 32, 1, 32, 0, 166, 33, 1, 32, 1, 11]);
try {
    const wasm_mod = new WebAssembly.Module(wasm_code);
    const wasm_instance = new WebAssembly.Instance(wasm_mod);
    let ret = undefined;
    for (let i = 0; i < 10000; i++) {
        ret = wasm_instance.exports.poc(1234);
    }
    print(ret);
}
catch (e) {
    print(e);
}
```

The result is different if it's JIT'ed on BBQ or not.

```
$ jsc --useConcurrentJIT=false --useBBQJIT=true --useOMGJIT=false ./poc.js
-1234

$ jsc --useWasmLLInt=true --useBBQJIT=false --useOMGJIT=false ./poc.js
1234
```

[Marcus Plutowski]

Pull request: https://github.com/WebKit/WebKit/pull/24554

[EWS]

Committed 274910@main (5f1ac6454783): <https://commits.webkit.org/274910@main>

Reviewed commits have been landed. Closing PR #24554 and removing active labels.